I picked this book up at Pulpfest this year. Although the format is based on the original Secret Agent X pulp, this is actually a new novel by Stephen Payne, with a few crossovers. Agent X visits a gangster's funeral disguised as a reporter. When another crook takes a swing at him, X intercepts the blow, prompting the mobster to say, "What are you? Some kinda damn superman, like that laughin' mook what dresses in black and prowls around at night?" This is a reference to the Shadow, of course. There is also a reference to the Pink Rat, an underworld dive from the Shadow novels, a few chapters later. The gangster also asks the disguised X if he thinks he's "a damn mind reader, like that Captain Whatsisname...?" Later, there is a reference to X having an adventure in a country called Teutschland with Hazzard. Payne is planning to chronicle the team-up between Secret Agent X and the telepathic Captain Hazzard (both created by Paul Chadwick) in a novel called Hell's Haven. Finally, at the end of the novel, X visits two of his aides at the clinic where they are convalescing, which is owned by a neurophysician and adventurer who is a friend of X's. This friend also has a secret facility in New York that specializes in treating criminals. While there, X runs into a Mutt-and-Jeff duo, one short and apish and the other wasp-waisted and rather handsome, both of whom insult each other viciously, and a golden-eyed giant of a man. Obviously, the latter is Doc Savage, accompanied by Ham and Monk.